These birds are not at all easy to identify but they are thought to be long-term residents of
the Caledonian pine forests and the only species endemic to Britain. They were identified from
59 10-km squares in the second Breeding Atlas (not recognised as separate species at the time of
the first). Recently it has been suggested that some of the bigger billed birds breeding in these
areas may be irrupting Parrot Crossbills. The plot thickens but, if they exist, the Scottish
Crossbill seems to be secure.